The present invention relates generally to integrated circuit (IC) designs, and more particularly to an apparatus for detecting a current and temperature of an IC.
In recent IC designs, the power supply network often requires some devices to stabilize the voltage near circuits that demand rapid current transitions. One of such devices is a decoupling capacitor coupled with a protected circuit in parallel between a supply voltage and a complementary supply voltage, such as ground. A capacitor controlling circuit is often coupled with the capacitor for coupling and decoupling the same in response to a control signal. During the operation of the capacitor, there may be a leakage current generated therefrom. In order to control the leakage current, it is desirable to have a detection circuit that is capable of detecting the leakage current.
Conventionally, a detection circuit is often implemented to detect the leakage current from the capacitor. Such detection circuit typically includes a metal-oxide-semiconductor (MOS) device coupled between the capacitor and ground. The amount of the leakage current flowing across the MOS device is linearly proportionate to the voltage difference between the gate and source of the same. Thus, the amount of the leakage current can be determined by measuring the voltage difference between the gate and source of the MOS device.
As semiconductor technology advances to nanotechnologies, the supply voltage of the IC can be as low as 1 volt, or even lower. Due to the low operation voltage, the leakage current becomes small, and hard to detect. This is particularly true when a change of the sensing voltage, which is the voltage difference between the gate and source of the MOS device, is proportionate to a change of the leakage current, only linearly. In other words, the sensing voltage is insensitive to a change of the leakage current when its level is low.
Moreover, the conventional detection circuit usually occupies a large area in the IC. When the leakage current to be detected becomes small, the area occupied by the detection circuit certainly needs to be reduced.
Thus, it is desirable to have a detection circuit of a compact configuration that can detect small current with an improved sensing sensitivity.